Why are there spools of copper and aluminum wire on top of the sink

Well you wanna do the wiring for the plumbing at the same time as the pipes, obviously. So you know it’s good 👌

It’s a crafted weapon from pretty early in the tech tree

we like to electrify our water around here

It’s a pipe cutter.

However, it looks like she is sticking it into an Elbow pipe, which is an odd choice. Additionally, you would need a saudering tool after that.